Trailer light trouble

Discussion in 'Other Repairs' started by bwanatony, Jul 18, 2006.

  1. bwanatony

    bwanatony New Member

    Messages:
    580
    State:
    Grand River Valley, Weste
    This is the closest forum for this question, I think.

    My trailer's brake & turn lights worked fine, but the running lights not at all.
    I replaced the bulbs, which looked a bit old, no change.
    I replaced the wiring, completely, stem to stern, harness & all, no change.
    I replaced the entire tail lights, no change.
    SO- it must be the truck (2001 Dodge Dakota), which has a factory type flip up round socket on it.

    I can fix anything but a car or a truck, does anyone know where I should start looking for a problem? A fuse? What?

    Thanks loads,
    Tony
     
  2. Phil Washburn

    Phil Washburn New Member

    Messages:
    7,680
    State:
    Shawnee OK
    Tony, go to o'reillys or autozone and buy a 5$ 12V testlight. you're gonna have to find out where the volts stop, my friend. you can spend a lot of money and time throwing parts at it.

    your truck may have a turn bulb, a stop bulb, and a tail lamp bulb. your trailer lights may just be one double filament bulb. it may be as simple as getting a trailer adapter from oriellys. go to a parts troe and ask them about an adapter harness.
     

  3. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Did you run a separate ground wire for each light fixture, tail/turn/side and side markers? I believe all plugs or wiring harnesses for boats have green, yellow, brown and white wires. The green is Rt. turn, yellow is left turn and the brown is stop/tail lights. The white is a ground. If you run a separate wire and connect it to the white and on the prime mover (towing vehicle) you run a separte ground to the white wire you will be in tall cotton. Most boaters believe the ground is through the trailer ball, and although it does ground, 95% of light problems is due to the ground. ALWAYS run a separte ground wire.
     
  4. 223Smitty

    223Smitty New Member

    Messages:
    478
    State:
    Indiana
    Tony- I have a trailer that will do the same thing on occasion. It has "marker" lights on the side of the trailer, which are wired in a series with all the lights. These are a stud-mounted light, which the stud also provides a grounding point. If things get alittle rusty behind the marker light, you'll lose the ground, preventing the tail/running lights from working (but all other lights will work). If your trailer has these, I'd take them off & start there 1st.

    Smitty
     
  5. bwanatony

    bwanatony New Member

    Messages:
    580
    State:
    Grand River Valley, Weste
    Thanks, you guys are great.

    No side marker lights, but the old lights had one double filament (1157) bulb, and the new tail lights have the same 1157 bulbs plus an additional small bulb to the side.
    The white wire is grounded securely to the trailer frame, and there's no ground wires coming off the tail lights.

    Being that I have the identical problem with both old and new lights & wiring, it's gotta be the truck.

    Thanks again & good fishing!
    Tony
     
  6. trnsmsn

    trnsmsn New Member

    Messages:
    1,214
    State:
    Missouri Originally Now I
    As Suggested Before, Go To The Auto Parts Store And Buy A 12 Volt Testlight. Then Disconnect Your Trailer Plug-In From The Truck. Next Turn On Your Running Lights On The Truck ONLY. Next Probe The Truck Receptacle With The Test Light, One Of Them Should Illuminate The Test Light.Sometimes The Cover Over The Socket Will Indicate Which Curcuit It Is Designated For.

    If You Have The Standard 4 Pin Set-Up On Your Boat Pigtail, It Will Be The Brown Wire, Connect The Boat Back To The Truck & Start Probing The Brown Wire Circuit Until The Light Goes Out, This Of Course Would Be Where You Are Getting Your Loss Of Power. If This Is So, I'll Bet It's At A Connection Point.

    In The Event That The Testlight Stays On All The Way To The Respective Lights, Then You Have a Ground Problem. Just As Awshucks Said, The Trailer IS NOT Grounded Thru The Ball, It Is Grounded Thru The White Wire In The Pigtail Which Connects To A Dedicated Ground Via Your Truck, HTH Elliot
     
  7. blackwaterkatz

    blackwaterkatz Active Member

    Messages:
    3,659
    State:
    Andrews, SC
    Tony, take a look at your fuses in the truck. Some vehicles have a fuse panel in/under the dashboard, plus another one under the hood. Use the owners maual if you have it to identify the one for your brake/tail/signal lights. If you don't have the owners manual, check the fuses individually for a blown fuse. This may save some time. If you don't find a bad fuse, then you will have to troubleshoot. You can purchase a very inexpensive tester for trailer lights at most auto parts stores, or walmart. It plugs into the 4-way connector on your vehicle and will show if things are working correctly.

    When wiring trailer lights, this is the standard:
    White = ground
    Brown wire = tail/clearance lights
    Yellow wire = left turn
    Green wire = right turn
     
  8. porboy

    porboy New Member

    Messages:
    629
    State:
    TX Panhand
    If this is a tilt trailer you may be losing ground at the hinge part. I had this trouble before and cost me all new lights and much time and trouble. Think of a pair of sissors, go to where the tilt is, ground the paint off where you can get a good ground between both parts of the trailer and run another ground wire between both parts. You will have to leave it long enough to be able to tilt without pulling into. It worked for me and might for you.
    Bill
     
  9. bwanatony

    bwanatony New Member

    Messages:
    580
    State:
    Grand River Valley, Weste
    Excellent, thanks!
    I guess I know what I'm working on tonight...
    Tight lines!
    Tony
     
  10. hoosier angler

    hoosier angler New Member

    Messages:
    63
    State:
    Arizona
    I would start at the truck side plug. Test the pins there first, if thats OK move to the trailer, Is this a new problem? Has it worked before on this truck. If it worked before Its probably in the connection or a ground. Do you have access to another tow vehicle for a quick backup and plug in test. That could narrow it down for you. Let us know what it was!
     
  11. JAinSC

    JAinSC Active Member

    Messages:
    1,514
    State:
    South Carolina
    This is why when I have a problem with trailer lights (and mine see salt water on occasion - only makes things worse) I have a standard procedure:

    1) Light candles
    2) Burn incense
    3) bow rythmically toward the trailer
    4) repeatedly chant in a low voice "please work, please work, please work ..."
     
  12. Georgiajack

    Georgiajack New Member

    Messages:
    345
    State:
    Georgia
    I had a similar problem a while back. It turned out th ground wire to the truck had gotten coroded, and wasn't making a good ground. The above advice about getting a test light is a good move if this is not your problem. I run mine with a ground to the truck, and one on the trailer(white wire) Good luck, and good fishin', Jack.
     
  13. Gringoloco

    Gringoloco Member

    Messages:
    426
    State:
    Ft. Belvoir, VA
    Name:
    Josh
    Sounds like a connection problem but are you 100% sure that you have everything hooked up properly?
     
  14. bwanatony

    bwanatony New Member

    Messages:
    580
    State:
    Grand River Valley, Weste
    Yes, everything is hooked up properly.
    Remember, same problem with two complete sets of wires & lights. It just can't be the trailer.
    I'll let you all know what I find working on the truck tonight.

    Thanks again,
    Tony
     
  15. Mutt

    Mutt Administrator Staff Member Supporting Member

    Messages:
    18,945
    State:
    Ca
    Name:
    Mutt
    kind of a silly question/answer here but are your tailights on the truck working? if so then check the wire going from the circuit where it ties into the tail lights on the truck to the plug.
     
  16. trnsmsn

    trnsmsn New Member

    Messages:
    1,214
    State:
    Missouri Originally Now I
    Hey Mutt, I Was Going To Suggest That But Being As He Stated That The Only Thing Inoperative Was The Marker/Running Lights, I Then Took It As A Given (Compliment To Him), That The Truck Lighting Was Fully Operational.

    I Guess Taking Things As A Given Sometimes can Be Considered To Be Better Than "ASS-UM-ING":lol: Elliot
     
  17. bwanatony

    bwanatony New Member

    Messages:
    580
    State:
    Grand River Valley, Weste
    Sorry, I forgot to mention that everything works 100% on the trucks own lights.
     
  18. Fishing Fred

    Fishing Fred New Member

    Messages:
    199
    State:
    Lillington, N.C
    Mutt answered your question. You almost have to have a test light to fix electrical problems. I do a lot of trailer lights. A lot of all kinds in the past. If the tail lights work on the truck and after everything you replaced you have to have a problem between the plug on your truck and where the taillight wire from the truck plug ties into the truck wiring harness. You license plate light wire is on this same circet. Its not a ground problem between your truck and trailer if any of the lights work on the trailer . Hope this helps you some. Wiring problems are not that hard if you take your time and trace everything out one wire at a time with a test light.
     
  19. Mr.T

    Mr.T Active Member

    Messages:
    2,554
    State:
    MO
    If you don't have one already, go to an auto parts store or Wally World and buy a "Trailer Circuit Tester" - it's a $4 item that you plug into your vehicle's wiring connector to verify whether everything is working there. You suspect the problem is in the way the vehicle is wired; this thing will tell you in a heartbeat.

    Here's an example of the tester: http://www.opentip.com/product_info.php?products_id=16244 - I don't know a thing about the store selling it and you can get it locally, I'm certain.

    If all the indicators on the tester light up properly, then the problem is in your trailer wiring. If not, it's in the vehicle's wiring.
     
  20. 223Smitty

    223Smitty New Member

    Messages:
    478
    State:
    Indiana
    Out of curosity, it your connector the "flat-4" style, or a 6-9 pin round?

    Smitty